Arduino Nano - LCD 20x4

This tutorial instructs you how to use LCD 20x4 display with Arduino Nano, how to program for Arduino Nano to display text on LCD 20x4.

Hardware Preparation

1×Arduino Nano
1×USB A to Mini-B USB cable
1×LCD 20x4
1×Jumper Wires
1×(Optional) 9V Power Adapter for Arduino Nano
1×(Recommended) Screw Terminal Adapter for Arduino Nano

Or you can buy the following sensor kits:

1×DIYables Sensor Kit (30 sensors/displays)
1×DIYables Sensor Kit (18 sensors/displays)
Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you. We appreciate your support.

Overview of LCD I2C 20x4

LCD I2C is made up of a standard LCD, an I2C module and a potentiometer.

The LCD Pinout

The LCD I2C uses the I2C interface to connect to Arduino Nano. It has four pins:

  • The GND pin needs to be connected to ground (0V).
  • The VCC pin is the power supply for the LCD and must be connected to VCC (5V).
  • The SDA pin is the I2C data signal.
  • The SCL pin is the I2C clock signal.
LCD I2C pinout

LCD Coordinate

The LCD I2C 20x4 has 20 columns and 4 rows, with the columns and rows being numbered starting from 0.

Arduino Nano LCD I2C coordinate

Wiring Diagram

The wiring diagram between Arduino Nano and LCD I2C

This image is created using Fritzing. Click to enlarge image

LCD I2C module Arduino Nano
Vin 5V

How To Program For LCD I2C

The LiquidCrystal_I2C library needs to be included in order to use the LCD.

  • Set up the LCD:

The LCD must be set up properly for it to work correctly.

  • Write to the LCD:

Writing to the LCD is easy thanks to the LiquidCrystal_I2C library.

#include <LiquidCrystal_I2C.h> // Library for LCD
  • Create a LiquidCrystal_I2C object with an I2C address, the number of columns, and the number of rows specified.
LiquidCrystal_I2C lcd(0x27, 20, 4); // I2C address 0x27, 20 column and 4 rows
  • Start up the LCD.
lcd.init(); //initialize the lcd lcd.backlight(); //open the backlight
  • Go to the column and row indicated by column_index and row_index respectively.
lcd.setCursor(column_index, row_index);
  • Display a message on the LCD.
lcd.print("Hello World!");

Explore the possibilities of what can be achieved with LCD by looking at the "Do More with LCD" section.


The address of the LCD may differ depending on the manufacturer. For our code, we used 0x27 as specified by DIYables.

Arduino Nano Code

/* * This Arduino Nano code was developed by * * This Arduino Nano code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * */ #include <LiquidCrystal_I2C.h> LiquidCrystal_I2C lcd(0x27, 20, 4); // I2C address 0x27, 20 column and 4 rows void setup() { lcd.init(); // Initialize the LCD I2C display lcd.backlight(); lcd.setCursor(0, 0); // move cursor the 1st row lcd.print("LCD 20x4"); // print message at the 1st row lcd.setCursor(0, 1); // move cursor to the 2nd row lcd.print("I2C Address: 0x27"); // print message at the 2nd row lcd.setCursor(0, 2); // move cursor to the 3rd row lcd.print("DIYables"); // print message at the 3rd row lcd.setCursor(0, 3); // move cursor to the 4th row lcd.print(""); // print message the 4th row } void loop() { }

Detailed Instructions

  • Click to the Libraries icon on the left bar of the Arduino IDE.
  • Search for "LiquidCrystal I2C" and locate the LiquidCrystal_I2C library created by Frank de Brabander.
  • Then, click the Install button to add the library.
Arduino Nano LiquidCrystal I2C library
  • Copy the code and open it with the Arduino IDE.
  • Click the Upload button in the IDE to send the code to the Arduino Nano.
  • Check the LCD for the result.
Arduino Nano display text on LCD
  • Experiment with altering the text and its location.

Guide for Choosing LCD I2C Displays

There are different types of LCD I2C displays you can buy. They mainly differ in background color and how you select the I2C address.

LCD I2C 20x4 Selection Guide

Color Options

Most LCD I2C displays come in two background colors:

  • Green
  • Blue

I2C Address Selection Options

With a Jumper

  • Allows you to switch between two I2C addresses.
  • Useful if you are using two LCDs at the same time.
  • Can be confusing if you are only using one LCD.
  • Takes up more space.

Without a Jumper

  • Has a fixed I2C address.
  • Very convenient if you are using only one LCD.
  • Recommended for most projects, as most use just one LCD display.

Video Tutorial

Do More with LCD

Custom Character

See Custom characters on LCD


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